Hydrophylic, olefinically unsaturated polyurethanes and their use as reactive emulsifiers

Abstract

The present invention relates to hydrophilic polyurethanes having a content of (i) olefinic double bonds (expressed as C═C, molecular weight 24) of at least 1.0% by weight and (ii) ethylene oxide units incorporated through polyethylene glycol of 20 to 80% by weight, which are based on the reaction product of a) 1.0 mole of a polyisocyanate component consisting of at least one organic polyisocyanate with b) 0.3 to 2.5 moles of at least one β,γ-ethylenically unsaturated ether alcohol containing 5 to 29 carbon atoms, c) 0 to 1.0 mole of at least one synthesis component containing at least two isocyanate-reactive groups and having a molecular weight of 62 to 2,000 and d) 0.25 to 0.85 moles of a polyethylene glycol component containing at least one polyethylene glycol having a molecular weight of 1,300 to 5,000, at an NCO/OH equivalent ratio, based on starting components a) to d), of 0.7:1 to 1.2:1. The present invention also relates to a water-dispersible coating composition based on a mixture of radical-curable synthetic resins containing unsaturated groups wherein the mixture contains A) 50 to 95 parts by weight of at least one non-water-dispersible synthetic resin containing unsaturated groups and having a molecular weight (M n of 500 to 10,000 and B) 5 to 95 parts by weight of a polyurethane component which possesses sufficient hydrophilicity to ensure the dispersibility of the mixture in water and which contains at least one of the previously mentioned hydrophilic polyurethanes.

What is claimed is: 
     
       1. A hydrophilic polyurethane having a content (i) of olefinic double bonds (expressed as C═C, molecular weight=24) of at least 1.0% by weight and (ii) ethylene oxide units incorporated through polyethylene glycol of 20 to 80% by weight, which comprise the reaction product of a) 1.0 mole of a polyisocyanate component comprising at least one organic polyisocyanate with   b) 0.3 to 2.5 moles of at least one β,γ-ethylenically unsaturated ether alcohol containing 5 to 29 carbon atoms,   c) 0 to 1.0 mole of a component comprising at least one compound containing isocyanate-reactive groups and   d) 0.25 to 0.85 moles of a polyethylene glycol component comprising at least one polyethylene glycol having a molecular weight of 1,300 to 5,000, in an NCO/OH equivalent ratio, based on starting components a) to d), of 0.7:1 to 1.2:1.     
     
     
       2. A water-dispersible mixture of radical-curable synthetic resins containing unsaturated groups comprising A) 50 to 95 parts by weight of at least one non-water-dispersible synthetic resin containing unsaturated groups and having a molecular weight Mn of 500 to 10,000 and   B) 5 to 50 parts by weight of a polyurethane component which possesses sufficient hydrophilicity to ensure the dispersibility of the mixture of A) and B) in water, wherein said polyurethane component comprises at least one polyurethane according to claim 1.   
     
     
       3. The hydrophilic polyurethane of claim 1 wherein said β,γ-ethylenically unsaturated ether alcohol contains 5 to 14 carbon atoms. 
     
     
       4. The water-dispersible mixture of claim 2 wherein said polyurethane component comprises at least one polyurethane according to claim 3.